Describe the bug

I'm willing to submit a PR to address this, but want to be sure I'm not misunderstanding something first...

The CMS.registerWidget() source takes four arguments:

export function registerWidget(name, control, preview, schema = {}) { ... }

but the typescript interface exported for it doesn't include the schema argument

registerWidget: (
      widget: string | CmsWidgetParam,
      control?: ComponentType<CmsWidgetControlProps> | string,
      preview?: ComponentType<CmsWidgetPreviewProps>,
) => void;

Additionally, the actual registerWidget function checks whether its first argument is an array, and if it is calls its self on each member of the array, but the typescript interface does not recognize this usage as valid.